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Goncalves" , Andrew Morton , Boqun Feng , Ingo Molnar , John Ogness , Mel Gorman , Peter Zijlstra , Thomas Gleixner , Waiman Long , Will Deacon Subject: Re: [PATCH v2 1/2] seqlock: Do the lockdep annotation before locking in do_write_seqcount_begin_nested() Message-ID: References: <20230623171232.892937-1-bigeasy@linutronix.de> <20230623171232.892937-2-bigeasy@linutronix.de> <20230626081254.XmorFrhs@linutronix.de> <20230727151029.e_M9bi8N@linutronix.de> <649fa1a7-4efd-8cc7-92c7-ac7944adc283@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <649fa1a7-4efd-8cc7-92c7-ac7944adc283@I-love.SAKURA.ne.jp> X-Rspamd-Queue-Id: A76E9120028 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: 83ejr5q6isconinz6th6d1pythjsgin5 X-HE-Tag: 1690813519-161200 X-HE-Meta: U2FsdGVkX19AwuDtS7u5lT+kxUVSloS7+3HowQW8WaHa7MC1pcWB1gBvyS5/W7m9W82FBt3F3bR70mF63XB6dt9T7xCF2K2QpG+Sq7cqdrVrP3nBazc2YjgT+qkVn6HwklVZ/A+vNReHQQFOfTMzZ59pZITis8oQa2x5DkNxojE24NaLINN0WalIiKe+mxKnvsFVMH7jmzrAkmhCvGhwDFOiraaofynqepjPjkRlu16yqu4Ed0zwmygguGtaOW3s965hLFZPEgSRvl8xhsJhxBGCzm2Z7jDLFRd8agl418npaMqI5FdPbyH6sWW/Z+nnAQoxWM9SBTMXAJZWaSL6UOcev36Fx5KHoX36OwZ1VQ+p1dMMvLFe0GpFznaa0fqARmeVEFy+cAoJcSMl4rmKWb0AV+uRof5/pgq8jMHlwMtaj71UNCj1N+2+hCUioYizkLMOVXh8xTnP0oofwvjpZDEy4U0c05wecqO+4/JNHZ9r7h9WZnFPWJIr/Gca9swfjS9zJIyblmBVyDSPP9/q6D8DnfSzSsakz/H9wVRzcRH2Y/mET1JmM28uKuMZv05x49IVIOT9qq7snvWF2c3NV6QfjX689XLkUh6b8sI91bE6SIG324OKC+2cq9OjOQdBpagRuapvlrUFYTtar9z1MoZLSHUYPTjMyAmrFvJXRJ4HqO+bs92/UGbEcp5cj3cxlmiBWyqHhDPl40LfxyZvoZwyMWWg2xPm/kaO9hcH/DaHue2goiOk2abfSrMSm1gBKzwcQ6w+j+OzF2KJ+Fekro2aBI3DKe1zaiS9QvCCbwYFZRTKMcAjC9heUylcytYKGSr93UDilBYSSv88d4KpvrcTclKCGKBrvXiiUQkzuTqLSdsnRyu6vfJkK9NR6E/SfOsuG+ZIIsa47gUFiyGrJjdn8qJmj+loUgHgHq9D/yGCHOPvy+w3O97YcdZ7FYwN494CsLwaAJHNWsr9GTJ zcX2gONX KICozZbvR6HuNNf+bK6qBiVmBTY87mR9AGWMm3YE78AHeL7ZoYBmCXVYikmD8J8A7ShPrRdjumrJcsEyq2DOqRv11TPEeLEnS8blBwNZgD4wEsmndiXQ58AAHrqJYOCDO+edB6XpTz6dsQGgNX1ZH5z5aCirNNwvsPbAMHSaeNb8VO04NWbIsx1fedN6E3D0iaKoJNbkOdvMUmT7hRbCi3rhug/BsBr0xvoweOjpp9LaDQBt/hb8zOAouPTYcU2va5HxQqfTX3hocAd+dX2a+13FeuFYGDktnAO+8++xefrdszxOV1yO9vWqrU4LMkByAKNnStCl9NIvkHeI= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat 29-07-23 20:05:43, Tetsuo Handa wrote: > On 2023/07/29 14:31, Tetsuo Handa wrote: > > On 2023/07/28 0:10, Sebastian Andrzej Siewior wrote: > >> On 2023-06-28 21:14:16 [+0900], Tetsuo Handa wrote: > >>>> Anyway, please do not do this change only because of printk(). > >>>> IMHO, the current ordering is more logical and the printk() problem > >>>> should be solved another way. > >>> > >>> Then, since [PATCH 1/2] cannot be applied, [PATCH 2/2] is automatically > >>> rejected. > >> > >> My understanding is that this patch gets applied and your objection will > >> be noted. > > > > My preference is that zonelist_update_seq is not checked by !__GFP_DIRECT_RECLAIM > > allocations, which is a low-hanging fruit towards GFP_LOCKLESS mentioned at > > https://lkml.kernel.org/r/ZG3+l4qcCWTPtSMD@dhcp22.suse.cz and > > https://lkml.kernel.org/r/ZJWWpGZMJIADQvRS@dhcp22.suse.cz . > > > > Maybe we can defer checking zonelist_update_seq till retry check like below, > > for this is really an infrequent event. > > > > An updated version with comments added. Seriously, don't you see how hairy all this is? And for what? Nitpicking something that doesn't seem to be a real problem in the first place? -- Michal Hocko SUSE Labs